The problems associated with providing electrical continuity from the inside of a sealed chamber to the outside world, without permitting leaks into the sealed chamber, are manifold and have been a challenge to those skilled in the art for a long period of time. The devices which enable wires, or cables, to pass from, for instance, a thermocouple located inside of a vacuum furnace chamber to the outside of the vacuum furnace chamber are identified as feedthrough devices. In the prior art the feedthrough devices include a housing member which threads into the chamber wall of the sealed chamber. The threads of the housing member have been wrapped in polytetrafluoroethylene tape to ensure a seal of the grooves around the threads. In the prior art there is a tube-like structure formed, within the feedthrough housing, so that wires from thermocouples, for instance, are passed through the tube-like structure. The end of the tube-like structure has a flared design and into the flared end there is located a tapered plug. The tapered plug has generally been polytetrafluoroethylene. The tapered has a hole (or holes) therethrough which accommodates the wires of the thermocouples. The tapered, or cone-shaped, plug is literally threaded onto, or passed over, the wires and is pushed into the flared end of the tube-like structure to effect a seal. The arrangement has at least five major problems. The prior art arrangement is not easy to employ in the field because "threading" the wires through the plug is difficult. The "threading" of the wires through the tapered plug is difficult because the holes in the tapered plug are of a small diameter, that is, of virtually the same diameter as the wires being passed therethrough, in order to create a seal. In addition, since the wires are very thin, they are mechanically weak, which adds to the difficulty. Secondly, after a period of time the polytetrafluoroethylene wrapping on the threaded extension "cold flows", or creeps, and the same is true of the tapered plug. Accordingly, the wrapping and plug no longer effect a compression around the pipe and the wires and they permit gases or air to pass along the threads as well as through the tapered plug. Thirdly, the prior art arrangement cannot accommodate a large number of wires coming from the chamber. Fourthly, the prior art arrangement does not provide the flexibility that is provided by the present arrangement. In addition, the prior art arrangement can only accommodate a limited temperature range in its use. In the present arrangement, there is employed a removable header and, hence, different headers can be employed to accommodate different uses of the feedthrough mechanism. The present header features a glass-to-metal bond which permits the wires from one side of the header to pass through a plate to the other side of the header while maintaining a very good seal over a relatively large range of temperatures.